Billboards present a particularly inviting structure for birds to rest and nest within, primarily due to the relatively remote locations of billboards and their often sunny perches. As a result, billboards have for years created a host of problems associated with bird nesting activities. Perhaps the most serious problem created by nesting birds are health risks from bird droppings. It is common for birds to spread diseases through their droppings, either through direct contact with the droppings, via droppings that mix with food and water sources, as a result of fecal dust from bird feces, and from the parasites that birds harbor, such as fleas, ticks and mites. When billboards are positioned in areas frequented by the general public, such as parks and playgrounds, these health risks are magnified.
Another problem associated with pest birds is the mess, stains and physical damage that results from bird droppings. Billboards positioned, for example, adjacent new car lots result in numerous bird droppings ruining the finishes on new cars parked on the lot. Billboards positioned on rooftops result in a pile-up of bird droppings on the roof and sometimes bird droppings dripping down the side of the building, which not only is unsightly but can result in damage to roofing and siding material.
U.S. Pat. No. 5,497,585 discloses a bird anti-perching device in the form of a plurality of rotatable rings strung consecutively on a cable supported above the top frame of a billboard. Birds attempting to land on the top frame of the billboard will necessarily have to land on the string of rings, which due to their free rotation do not provide a stable landing platform, forcing the birds to fly away. However, the rings do not prevent birds from landing and nesting in the support frame of the billboard, which is where birds desire to nest due to the somewhat enclosed nature of the structure.
Other bird anti-perching devices include expandable foam, spikes, electrical shock wires, coils, mechanical wires, and gels that birds do not like to step in.
Attempts have been made to string netting around billboards and their support structure, as well as around other structures, but it has proven difficult to securely fasten the netting so that it remains in tact, and to arrange the netting in a manner that does not interfere with maintenance of the billboard and replacement of billboard signs. Typically, netting is secured around as much of the structure as possible in order to protect every possible landing site from bird intrusion. However, such over-protection of the structure is expensive and often interferes with maintenance and repair.
As a result, there is a need for improved methods of protecting billboard structures from nesting birds, which at the same time allows maintenance personnel maximum access to the billboard.